Women who are less than nine weeks pregnant can safely have medical abortions at home, according to the head of a government-backed pilot project.

Abortion services for the 20,000 women who seek a chemically induced abortion every year could be transformed should the Department of Health's official evaluation of the pilot confirm initial findings. But it is also likely to provoke controversy from anti-abortion campaigners who will claim that home abortions would make the procedure easier and therefore lead to more women having terminations.

Shirley Butler, the project manager of one pilot which has tested the abortions with 172 women patients since 2004, told the Guardian: "We haven't had any significant problems apart from one woman who had a slightly heavy bleed. In my opinion medical abortions outside of acute hospitals seem to be safe." She added that women who took part in the trial were positive about it.

Ms Butler stressed that the results were preliminary and were now being officially evaluated. She also asked for her hospital not to be named for fear of reprisal attacks from pro-life campaigners. St Mary's hospital in London confirmed that it is undertaking the second trial.

Chemical abortions are available before the 12th week of pregnancy. Women who request it take one tablet of mifepristone at a hospital then return two days later to take four doses of misoprostol which causes a termination within hours. Usually women remain in hospital after taking the second pills until the abortion is complete. Under the trials they took both sets of pills within local community clinics to test the theory that it is safe to be outside hospital, and therefore at home.

A Department of Health spokeswoman said the scheme, which was revealed yesterday by the journal Nursing Standard, had not yet been evaluated. "No changes to the way abortions are carried out will be approved unless we are content that there is no risk to the women's safety."

Anne Weyman, chief executive of the Family Planning Association, said: "Medical abortion is a highly safe and effective procedure. Completing the second stage at home can provide greater comfort and privacy."